1. Field of the Invention
The present invention and relates generally to mechanized agricultural tree harvesters that utilize shaker heads to shake fruit and nut trees, and more particularly to such a harvester having a tree sensing device and a related system that automatically detects, clamps and shakes trees.
2. Description of the Prior Art
Tree harvesters for shaking nut and fruit trees to cause nuts or fruit-to drop to the ground for harvesting to are well known in the prior art. R. W. Brandt, Jr. was a prolific inventor in this field and his U.S. Pat. Nos. 3,163,458; 3,220,268; 3,221,567; and 3,318,629 describe various features of tree harvesters and shaker heads that are still used in current devices. A harvester having an apparatus for cooling shaker heads is described in U.S. Pat. No. 5,103,625 issued to Kenneth L. McCrill.
When the harvest time of a particular crop occurs, thousands of trees in orchards become ripe at the same time. The shaking of these thousands of trees is a time consuming process, that must be completed quickly, and it is therefore advantageous to create systems that complete the tree shaking operation as quickly as possible, such that more trees can be harvested more rapidly while the crop is ripe and before it becomes over ripe and then spoiled. The present invention is an automation of the tree harvester shaking process, and it includes a tree sensing device along with a system for automatically deploying the shaking head, clamping the tree, shaking the tree, releasing the tree and returning the shaker head to the harvester.
The tree harvester of the present invention includes an automated tree sensing and shaking control system that is incorporated into a prior art tree harvester. Such harvesters generally operate by being driven to a location proximate a tree to be harvested, and extending a shaker head having tree clamping pads towards the tree. The shaker head includes movable jaws that clamp the tree and a shaker head motor is then activated to shake the tree. Thereafter, the jaws are released to unclamp the tree and the shaker head is moved back to the harvester, which is then driven to the next tree whereupon the shaking process is repeated.
In the present invention a tree sensing device, such as an ultrasonic sensor, is mounted upon the harvester, preferably though not necessarily upon the shaker head. Predetermined tree distance values and other shaker head control parameters are input into a programmable logic control (PLC) device of the control system. When the harvester is driven to a location next to a tree, the operator initiates an automated tree shaking cycle in which the tree sensor locates the tree and provides distance values to the tree as input signals to the controller. The controller compares the distance values to the tree with the predetermined tree distance value and provides shaker head control signals that cause the shaker head to automatically move outward towards the tree. The shaker head outward motion is halted when the inputted distance values to the tree are equal to or less than the predetermined tree distance values. The control system then provides control signals to the shaker head components to cause the shaker head to clamp the tree, to shake the tree, to unclamp the tree and to move the shaker head back to the harvester. Further control input signals to the controller include engine RPM signals for controlling the engine RPM and tree shaking time signals for controlling the duration of the tree shaking step. The present invention has proven to be generally more rapid and more efficient in harvesting a tree orchard than an operator controlled harvester.
It is an advantage of the harvester of the present invention that it includes an automated tree shaking cycle.
It is another advantage of the harvester of the present invention that it includes a control system and a tree sensing device that provides tree distance values for controlling the shaker head movement towards a tree.
It is a further advantage of the harvester of the present invention that it includes a programmable logic control (PLC) device that receives predetermined tree shaking process variables, and which compares the predetermined process variables with input signal values to provide output control signals to various components of the harvester to automatically control the tree shaking process.
It is yet another advantage of the present invention that it includes an automatic tree locating and shaking system that shakes trees in an orchard more rapidly and efficiently than a human operator.